The increase in the number of diagnosed cases of autism in recent years has sparked concern that environmental toxins may cause this complex disorder. A new study found, however, that exposure to Rh immune globulin preserved with mercury-containing thimerosal before birth was no higher for children with autism. The study led by Judith Miles, at the University of Missouri-Columbia, will be published online in the American Journal of Medical Genetics Part A available online via Wiley InterScience at http://www.interscience.wiley.com/ajmg.
Although experts anticipate that autism will be the first behavioral/psychiatric disorder for which major genes will be identified, there is still fierce debate that thimerosal, a preservative commonly used in vaccines and is almost 50 percent ethylmercury, is responsible for the rise in the disorder. Autism diagnoses have increased significantly during the last two decades, which coincides temporally with the addition of five pediatric vaccines to the immunization schedule, exposing children to increasing doses of ethylmercury, a known toxin. Though the vast majority of studies indicate no association between vaccines and autism, the FDA, CDC and American Academy of Pediatrics, recommended that thimerosal be removed from all routinely recommended early childhood vaccines; this was accomplished by 2002.
The current study investigated thimerosal exposure during pregnancies that resulted in the birth of a child subsequently diagnosed with autism. Rh negative women are routinely treated with Rh immune globulin (RhIg) during the third trimester to prevent hemolytic disease, in which the mother's immune system attacks fetal blood cells. Like many vaccines, RhIg manufactured in the U.S. contained thimerosal prior to 2001. Since young fetal brains are more susceptible to neurotoxic effects, researchers led by Judith Miles, MD, PhD, of the Thompson Center for Autis
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